Ответ:

1. If you use (use) less paper you WILL SAVE (save) the rainforests.

2. The polar bear WON'T BECOME (not/become) extinct if we STOP (stop) global warming.

3. You WILL WASTE (waste) electricity if you LEAVE (leave) your computer on standby.

4. WILL the ice caps MELT (melt) if temperatures RISE (rise)?

5. If you RIDE (ride) your bike you WON'T CAUSE (not/cause) air pollution.

6. We WILL REDUCE (reduce) waste if we RECYCLE (recycle) rubbish